Hepatic Anatomy

• Canine Liver Anatomy:
  • Inferior Vena Cava
  • Aorta
  • Hepatic Artery
  • Gall Bladder
  • Portal Vein
  • Common Bile Duct

Liver Function

• Nutrient Metabolism:
  • Carbohydrates
  • Proteins
  • Lipids
• Protein Synthesis:
  • Albumin
  • Coagulation Factors
  • Complement Factors
  • Haptoglobin
  • Ceruloplasmin
  • Transferrin
  • Protease Inhibitors
• Liver Function Tests (LFTs):
  • Measure enzymes & other substances made by liver:
  • ALP (Alkaline Phosphatase)
  • ALT (Alanine Aminotransferase)
  • AST (Aspartate Aminotransferase)
  • GGT (Gamma-glutamyl Transferase)
  • Bilirubin
  • Damage Indicators:
  • Damage to Liver
  • Damage to Hepatobiliary Tree
• Storage:
  • Iron, Copper, Vitamins A, D, & B12
• Excretion:
  • Bile Salts, Bilirubin
• Important Note:
  • Liver enzymes are intracellular and are released into the bloodstream upon cellular damage.

Acute Liver Failure

• Drug/Toxin Induced:
  • Description:
  • Occurs suddenly after a toxic event damaging 75% of the liver.
  • Common agents: Acetaminophen, barbiturates, chemotherapeutics, antifungals, arsenicals.
  • Typically Related To:
  • Overdose, not therapeutic levels.
  • Clinical Signs:
  • Anorexia, Vomiting, Diarrhea
  • Jaundice/Icteric serum
  • CNS signs
  • Diagnosis:
  • History, Liver Function Tests
  • Treatment:
  • Prompt treatment of known toxin ingestion
  • Supportive care

Chronic Liver Failure

• Drug/Toxin Induced:
  • Description:
  • Results from long-term use of drugs, often at therapeutic levels, leading to liver damage.
  • Common Agents:
  • Anticonvulsants, glucocorticoids, NSAIDs, methimazole.
  • Clinical Signs:
  • Anorexia, Weight loss
  • Jaundice
  • Ascites
  • Weakness
  • Diagnosis:
  • History, Liver Function Tests, Biopsies
  • Treatment:
  • Stop medications if possible
  • Supportive care

Infectious Canine Hepatitis (ICH)

• Cause:
  • Caused by Canine Adenovirus 1.
  • Relatively uncommon due to vaccinations.
• Effects on Liver:
  • Causes Hepatic Necrosis.
• Clinical Signs:
  • Fever, Lethargy, Depression
  • Pale MM, Petechial Hemorrhages
  • Anorexia, Vomiting
• Diagnosis:
  • Bloodwork
• Treatment:
  • Supportive care

Leptospirosis

• Characteristics:
  • Caused by spirochete organisms that can infect all animals.
  • Typically associated with kidney infection; spread via urine.
• Risk Factors:
  • Outdoor dogs are most at risk.
• Clinical Signs:
  • Acute Renal Failure with hepatic involvement
  • Dehydration, Vomiting, Jaundice
• Diagnosis:
  • Lab work, Serology
• Treatment:
  • Fluid support, Antibiotics (Doxycycline)
  • VACCINATION

Cholangiohepatitis

• Nature:
  • Ascending bacterial infection up the bile duct, primarily seen in cats (especially Persians).
  • May also involve the pancreas.
• Clinical Signs:
  • Anorexia, Vomiting
  • Weight loss, Dehydration, Fever, Jaundice
• Diagnosis:
  • Lab work, Liver biopsy
• Treatment:
  • Antibiotics, Supportive care
  • Feline Triaditis: Involves IBD, Cholangiohepatitis, and Pancreatitis.

Hepatic Lipidosis

• Overview:
  • Most common Hepatopathy in cats.
  • Typically affects adult, obese cats with a recent history of anorexia leading to acute weight loss.
• Mechanism:
  • Excess fat mobilizes for energy and accumulates in the liver, causing failure.
• Clinical Signs:
  • Obese cat, recent weight loss
  • Anorexia, Depression, Jaundice
• Diagnosis:
  • History, Lab work, Biopsy
• Treatment:
  • Supportive care, Feeding tube for caloric support.

Neoplasia

• Overview:
  • Presence of primary and metastatic tumors in both dogs and cats; metastatic tumors are more common.
• Clinical Signs:
  • Can vary; a history of cancer diagnosis can be indicative.
• Diagnosis:
  • Imaging (Radiographs, Ultrasound, CT), Biopsy
• Treatment:
  • Surgery for primary neoplasia.

Portosystemic Shunts

• Description:
  • Vascular anomalies (congenital) allowing portal blood to bypass the liver.
  • More common in dogs (e.g., Schnauzers, Yorkies); symptoms generally emerge before 6 months of age.
• Types:
  • Intrahepatic (large dogs)
  • Extrahepatic (small dogs & cats)
• Clinical Signs:
  • Failure to thrive, neurologic signs, GI signs (vomiting, diarrhea), small liver.
• Diagnosis:
  • History, Lab work, Imaging (Portal Scintigraphy, Contrast portography)
• Treatment:
  • Surgery